You can't restore the web-browsers cache, which is why if you are using the web-based version of Twine 2 it is a good idea to backup your story(s) using the Archive option.
Did you use the Publish to File option to create a HTML file version of your story?
If you did then you can use the Import From File option to recreate your story from the HTML file, that option can also import Archive files.
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Did you use the Publish to File option to create a HTML file version of your story?
If you did then you can use the Import From File option to recreate your story from the HTML file, that option can also import Archive files.